#include <stdio.h>
void swap(int* a, int* b);
int main(void)
{
    int i = 1, j = 2;
    swap(&i, &j);
    printf("i = %d, j = %d\n", i, j);
    return 0;
}
void swap(int* a, int* b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}